A multiplexed electrohydraulic type of control system has to be provided with some kind of electric power source and means of communication with the control and supervision station, through which to interface with the operator. The ideal way to avoid use of an undersea umbilical with electric cables between the platform and the template would be to provide the undersea control module with its own power supply source and/or place, together with means to enable it to communicate directly with the platform through the undersea environment it which it lies. Furthermore, the need to develop various other kinds of technology connected with idea is why it has not yet gained the degree of reliability and safety needed in the control of undersea production systems.